When, for example, an automobile or other vehicle or an industrial machine is used, vibrations of an engine or other parts, resonance caused during traveling or operation, and many other harmful vibrations may occur. Therefore, a dynamic damper may be adopted to inhibit such harmful vibrations. The dynamic damper may be configured so that a tubular member, which is attached to a target member to be inhibited from vibrating, and a tubular mass body, which coaxially surrounds the tubular member, are coupled by an elastic coupling section formed of a rubber elastic body (Patent Literature 1). According to Patent Literature 1, the mass body is prevented from falling off due, for instance, to fracture of the elastic coupling section by setting the outside diameter of the head of a bolt for fastening the tubular member to the target member to be larger than the inside diameter of the mass body.